To participate in Crimson Days, players must obtain the Quest "Crimson Bonds" from Lord Shaxx; note that players must be level 40.[1]
Completing the the quest, which involves completing 7 Crimson Doubles matches in a fireteam, rewards the Crimson Crest emblem.

Crimson Doubles is a 2v2 Crucible mode where killing one player on the opposing team will cause the surviving player to gain the "Heartbroken" buff to avenge his or her teammate. "Heartbroken" maxes out the affected player's Armor, Recovery, and Agility stats and increases weapon reload speeds; players affected by "Heartbroken" also gain a fiery red aura to mark them. Random rewards from each match include shaders, Ghost Shells with a random Defense value above the player's current Ghost Shell up to 320 Defense, and Crimson Candy.[1] In addition, daily bounties are offered by Lord Shaxx which can drop Nightfall-tier rewards.

Crimson Candy is a consumable used to activate a 30-minute buff called "Crimson Connection" among all members of a fireteam. "Crimson Connection" increases experience gains for all of a player's equipped weapons. Only one fireteam member needs to use a Crimson Candy to buff the entire fireteam.

As with other special events, the Tower gains a unique set of decorations for the duration of the event. The Crimson Days banner replaces the original banners in the Tower Plaza, and heaps of red flowers fill the planters and carpet the ground.

Coinciding with the arrival of Crimson Days, all players were granted two free Rare Emotes: "Yes" and "Nope", both of which can be found in the Emote kiosk in the Tower Hangar.